This advisory also applies to the corresponding versions of
Kubuntu, Edubuntu, and Xubuntu.

The problem can be corrected by upgrading your system to the
following package versions:

Ubuntu 8.04 LTS:
fuse-utils 2.7.2-1ubuntu2.3

Ubuntu 9.10:
fuse-utils 2.7.4-1.1ubuntu4.5

Ubuntu 10.04 LTS:
fuse-utils 2.8.1-1.1ubuntu3.1

Ubuntu 10.10:
fuse-utils 2.8.4-1ubuntu1.3

In general, a standard system update will make all the necessary changes.

Details follow:

It was discovered that FUSE would incorrectly follow symlinks when checking
mountpoints under certain conditions. A local attacker, with access to use
FUSE, could unmount arbitrary locations, leading to a denial of service.